Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
237 PM EDT Sun Oct 28 2018

Valid Oct 28/1200 UTC thru Nov 01/0000 UTC

...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...

12Z Model Evaluation...with Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: Non-CMC general model blend
Confidence: Slightly above average

19z update: Overall the rest of 12z guidance agrees well previous
guidance, minus the CMC which continues to too far south and
slower.The ECMWF is a bit stronger with the southern stream
shortwave across Texas by the end of the forecast period (01.00z)
but overall the differences are minor enough that a non-CMC
general blend (ECMWF/GFS/NAM/UKMET) would suffice for the CONUS.

---previous discussion---
Through the middle of next week, the synoptic pattern across the
CONUS is expected to evolve from a western ridge/eastern trough to
a western trough/eastern ridge with an active storm track across
the central US as a result. In general, outside of the CMC, the
main deterministic models are in good agreement with the mass
fields. During the transition, a northern and southern stream
piece of energy will push out into the central US, helping to
carve the western/Rockies trough.

The CMC is far too south with the southern energy, taking it well
into Mexico while the rest of the guidance agrees on a path more
through west-central to central Texas by 01.00z. For the northern
stream energy, the CMC is too flat and fast.

As a couple waves of low pressure lift through the southern US
into the lower Great Lakes, several rounds of precipitation are
expected to break out. There is better model agreement compared to
24 hours ago with the placement of the QPF axis on Tuesday and
Wednesday. Some subtle magnitude differences continue but overall,
the 12z NAM/GFS look similar to the 00z UKMET.

With the better consensus in the models this cycle, a general
model blend (non-CMC) is preferred.


Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml

Taylor